1. Field of the Invention
The field of invention relates generally to an apparatus, method, system, computer program and product, each capable of compressing a multivalue image with control of memory space requirement.
2. Description of the Related Art
In image processing systems, multivalue images, such as color images, are often compressed to save memory space or to reduce transmission time. For example, a lossy compression method such as JPEG may be applied to a multivalue image. However, when the multivalue image contains a high contrast edge, such as a character or a line, image quality may be degraded during the compression process.
One solution to this problem is to apply different compression methods to different sections of the multivalue image. For example, the multivalue image may be segmented into a foreground section and a background section. A first compression method, such as a lossless compression method, may be applied to the foreground section. A second compression method, such as a lossy method, may be applied to the background section.
However, in order to compress the multivalue image with high compression rate without suppressing image quality, the above-described method often requires highly accurate image segmentation. This often leads to increased computation load, thus requiring greater memory space.